1. Field of the Invention
The present invention relates to a wireless LAN system, a method for providing network services, and a medium storing a program to provide network services.
2. Description of the Prior Art
Any known wireless LAN system is constructed of a radio terminal (which functions as the access point) and one or more mobile units. The radio terminal has an appropriate antenna so that the wireless LAN system provides network services within the reach of radio waves emitted by the antenna. The mobile unit also has an appropriate antenna so that it receives said network services within the reach of radio waves. Both radio terminals exchange communications in conformity with an appropriate standardized procedure.
There have recently appeared stores who permit their customers to use the access point therein. If such stores are close to each other, they are required to intentionally limit the range of their network services. A conventional way to achieve this object is to limit the intensity of radio waves emitted by the wireless terminal at the access point.
The wireless LAN system of conventional type mentioned above has the difficulties in limiting the range of network services simply by controlling the intensity of radio waves, depending on the environmental conditions such as line-of-sight distance.
Although it is possible to limit only directionality by using directional antennas, this does not solve the problem with the distance of radio wave propagation. Although it is also technically possible to use highly active directional antennas (such as active array antennas), this is not a practical solution in view of their high cost for simple network services.